Helix wire anode



Jan. 10, 1961 sQB. TuwlNER HELIX WIRE ANoDE Filed om. 15, 1958 'i F |G.4.

FIGB.

i "be United @rates arent i HELIX WIRE ANODE Sidney B. Tuwiner, Baldwin, N.Y., assignor to Phelps Dodge Corporation, New York, N.Y., a corporation of New York Filed Oct. 15, 1958, Ser. No. 767,391

4 Claims. (Cl. 204-284) This invention relates generally to the electrowinning of copper in a system wherein there is provided an electrolytic cell having an insoluble metallic anode and a metallic cathode upon which the copper is deposited from the electrolyte upon the cathode; the invention relating more particularly to an improved anode for use in such a system.

In U.S. Patent No. 2,792,342, the application for which was filed by me January 26, 1956, I have described a system for the electrowinning of copper in which an anode in the form of a foraminous grid, and preferably in the form of a stainless steel woven wire mesh, is used; the electrolyte in the system comprising sulfuric acid, sulfates of copper and ferrous and ferric iron. The anode described in that patent provides an effective area wetted by the liquid electrolyte much larger than the effective area of an anode having a planar surface; some of the advantages of which, among others, are that the increased wetted area permits of operation of the electrolytic cell with a cell voltage below that which generates excessive oxygen and sulfuric acid at the anode. Also, the amount of electrical energy for copper electrowinning may be reduced over that required when planar anodes are used.

The present invention provides an improved anode for an electrolytic cell in a copper electrowinning system. The anode provided by the invention has an effective wetted area in the electrolytic cell which is materially greater than the effective wetted area of the anodes disclosed in the above mentioned U.S. Patent No. 2,792,342, with consequent materially increased electrical eiciency in operation of the electrolytic cell. According to this invention, the anode is made by mounting a number of wire helixes under tension in a frame suitable for suspending the helix Wire anode in conventional manner in the electrolyte in the electrolytic tank. The helixes are made of stainless steel wire and the helixes are mounted in the frame preferably so that their long'axes lie vertically in spaced parallel relation; with the turns of wire of successive helixes overlapping each other.

For convenience of description, the term helix, as used herein, has reference to a length of wire in the form of spiral which is made of a number of turns or coils. That is. as used herein, the term helix has reference to a length of spirally formed wire, whereas the term coil has reference to the individual turns which form the helix.

In my preferred construction successive helixes mounted on the frame have coils turned in opposite angular directions. That is, each helix is wound in a direction opposite to that of its next adjacent helix. In this latter mentioned construction each turn of Wire in any given helix crosses and contacts a corresponding turn of wire in the helix to each side of the said given helix with the result that the current introduced at one end of the coils is not constrained to tlow through a single wire but the current has paths of ow provided by the junctures where the wires in the helixes cross and contact the wires 'ice of their neighboring helixes with the result that the ohmic resistance to flow of current through the anode made up of a plurality of Wire helixes is materially reduced. Hence the helix anode according to the invention not only has larger effective wetted surface per unit area (measured as a planar surface) and a larger wetted surface than a comparable area of a wire mesh electrode but its use also permits of a reduction in cell voltage; improved cathode current density and current efliciency characteristics; andalso reduces the probability of anode corrosion under conditions of unwanted or accidental cessation of electrolyte circulation.

In one embodiment of my invention, I have used stainless steel wire 0.080 inch in diameter. The wire is preferably wound in a spiral coil of l/2 inch outer diameter in a tight coil and then mounted in suitable lengths of helixes on a rectangular frame made of stainless steel structural members so that the helixes are stretched under tension to give the coils a pitch of about 0.09 inch. Successive helixes are mounted with their longitudinal axes in parallel spaced relation, spaced apart a distance equal to half the diameter of the coils, with coils of successive helixes turned in opposite angular directions. That is, any given helix, when mounted on the frame, has its coils of wire turned in the opposite angular direction from that of the coils in the helix on each side of that given helix. The result is that each turn or coil crosses and engages, or contacts, the corresponding turn or coil of its next adjacent neighbor, with consequent reduction of ohmic resistance to iiow of current through the effective area of the anode.

Although the novel features which are believed to be characteristic of the invention are pointed out in the annexed claims, the invention itself as to its objects, and advantages, and the manner in which it may be carried out, may be better understood by reference to the following more detailed description taken in connection with the accompanying drawings forming a part hereof, in which:

Fig. 1 is a view in elevation of an anode embodying the invention;

Fig. 2 is an end view of the anode illustrated in Fig. l;

Fig. 3 is a partial view to larger scale illustrating my preferred manner of mounting the wire helixes in the anode frame; and

Fig. 4 is a view on line 4-4 of Fig. 3.

Referring now to the drawings in which like reference characters indicate like parts throughout the Vseveral views, the anode A comprises, in general, a rectangular frame 10, in which is mounted a plurality of wire helixes 11 suiiicient to till the entire area of the frame; the frame 10 being suspended on a suspension copperbar B by means of vertical stainless steel hanger members 13. As in conventional practice the end 14 of suspension bar B rests on a copper bus bar 15, in turn resting on the top edge of the wall 16 of the electrolytic tank T, shown conventionally in dotted lines. The other end of the bar B rests upon an insulation block 18, in turn resting upon the top edge of wall 19 of the electrolytic tank T. It will be understood that the cathode (not shown) adjacent the anode A in the electrolytic tank, will be suspended in conventional fashion in the tank on a suspension cross bar similar to suspension bar B, one end of which will rest upon bus bar 20 and the other end of that cross bar of the cathode will rest upon an insulation block 21. This is conventional and in this arrangement the direct current employed flows from the source, through the anode, through the electrolyte, through the cathode, back tothe source. i

The frame 10 of the anode is made of stainless steel bar stock and is constructed in rectangular shape to be suspended in the electrolyte in tank T. It comprises a horizontally disposed T-shaped, upper, or top, rail 23, having a body portion 24 and an integral rib 2S running longitudinally along the top rail (see Fig. 4); a corresponding horizontally disposed, T-shaped, lower, or bottom, rail 23a and vertical end, or side, rails 22, 22a. A series `of small holes 26 is provided in the rib V25 and these holes 26 are spaced, as shown, on 1A inch centers along the full length of the rib of the top rail 23. These holes are for mounting the helixes of wire, as explained later on, having a diameter of 1/2 inch. A like number of similar holes 26a is provided in rib 25a of bottom rail 23a. The vertical side rails 22, 22a may be rectangular in cross section; and, if desired, the top and bottom rails 23, 23a, may be rectangular in cross section to eliminate the rib; in which case the mounting holes are drilled in the main bodies of the top and bottom rails. The side rails 22, 22a are secured at their upper and lower ends, as by welding, to the outer ends of top and bottom rails 23, 23a, to form a rectangular shaped frame 10, as illustrated in Fig. l; or, these frame members may be secured together by other suitable means. Welded, or otherwise secured, to the upper rail 23 are a number of spaced vertically disposed stainless steel bars 13, serving as hanger rods for the frame. As shown. there are three equally spaced hanger rods. The upper ends of the hanger rods 13 are sandwiched between a pair of copper bars 12, 12a making up the suspension bar B.

The hanger rods are removably secured at their upper ends to the suspension bar B by bolts 27.

Mounted on the frame of the anode are a plurality of stainless steel wire helixes 30. 30a sucient to ll the entire area bounded by the top and bottom rails 23, 23a and vertical end frame rails 22, 22a. Each helix 30, 30a is made of stainless steel wire. In the preferred embodiment of my invention, I employ stainless steel helixes made of `wire 0.080 inch in diameter wound in spirals 1/2 inch outside diameter. The helixes are tightly wound in fabrication and then mounted in the frame in suitable lengths so that the coils are stretched and placed under tension to have a pitch of 0.09 inch. At each end of each helix there is a bent portion which serves as a hook 31 which may be hooked through corresponding oppositely disposed holes 26, 26a, in the ribs 25, 25a. Thus hook 31 of helix 30 is hooked through a hole 26 and hook 31a of helix 30 is hooked through hole 26a (see Figs. 1 and 3), and hooks 31 and 31a of helix 30a are hooked through corresponding oppositely disposed holes. It is significant to note that in my preferred embodiment (see Fig. 3) helix 30 has its coils turned in counterclockwise direction, looking down from above, whereas, helix 30a next adjacent to helix 30, has its coils turned in clockwise direction, looking in the same direction. In other words, each helix, as shown in Fig. 3 is coiled in the direction opposite to that of its adjacent helixes. Or, stated another way, successive helixes throughout the entire frame have their turns or coils running in opposite directions. This is an advantage because the holes 26, as shown, are on 1A inch centers and the helixes are wound to have a diameter of 1/2 inch, and hence the coils, which are mounted under tension, overlap. At the junctures where the wires cross each other, there is contact between them. Consequently, current passing through the copper suspension bar B, through hanger rods 13, through the helixes of the anode, is not constrained to pass from rail 23 to rail 23a through separate individual helixes in single spiral paths but the coils are criss-crossed, so to speak, so that the current may easily pass through the intertwined, overlapping coils of adjacent helixes. Hence, the arrangement provides means whereby the electrical current is distributed over the entire area of the helixes with a minimum of ohmic resistance.

It will be understood, of course, that the size of the frame 10 will be such as to be accommodated in the electrolytic tank in conventional fashion. By way of specific example, the frame may have side rails 22, 22a which are 37 inches high and top and bottom rails 23, 23a which are 36 inches long and the side rails may be made of stainless steel bar stock 1/2 inchx 3A inch at stock and the top and bottom rails of l/z inch x 11/2 inch at stock. An anode made according to the foregoing description provides a ratio of at least 4.0 sq. ft. of eEective anode area `for each square foot of peripheral or planar area on each surface.

The sizes of the wire may vary and I prefer to `use wire that will produce as much surface area per unit length as possible, consistent with adequate strength and adequate current carrying capacity, since sagging of the wire in the frame is to be avoided.

The examples above described refer to stainless steel construction. However, in certain kinds of electrolytic processes in which insoluble anodes are used the helix anodes may be `constructed of lead coated .copper or other suitable insoluble current conducting material, having in mind the nature of the electrolyte employed and thepurpose of the system.

The terms and expressions which have been `employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. A helix wire anode for use in a system for electrowinning of copper, or the like, which comprises a conductive suspension bar, a frame having top, bottom and end rails, said frame being secured to said suspension bar and having a peripheral shape suitable for suspension in an electrolytic tank containing liquid electrolyte, and a plurality of helixes of wire which is not corroded by the electrolyte, each of said helixes comprising coils of uniform diameter and having its opposite ends connected to opposed rails of said frame with the long axes of said helixes lying parallel to each other a distance apart which is substantially less than the outside diameter of said coils and each of said helixes having its coils turned in the opposite angulardirection from the angular direction of the turns of the coils of the next adjacent helix, the coils of each helix being spaced apart a distance suicient to cause overlapping and contacting of each coil with the adjacent coils of the next adjacent helix and said helixes occupying substantially all of the area bounded by said frame, so that the effective wetted surface of a unit area of said anode when it is placed in operative position in the electrolyte in the electrolytic tank is materially greater than the effective wetted surface of a like unit area of a planar anode, said contacting coils of wire providing conductive paths for the distribution of electrical current over the entire area of the helixes within said frame with a minimum of ohmic resistance.

2. A helix wire anode constructed according to claim l in which the long axes of said helixes lie apart a distance equal to about half the diameter of said coils.

3. A helix wire anode constructed according to claim l in which said frame and helixes are of stainless steel.

4. A helix wire anode constructed according to claim 2 in which the frame and helixes are of stainless steel.

References Cited in the tile of this patent UNITED STATES PATENTS 799,061 Kellner Sept. 12, 1905 1,749,952 Lichtman Mar. 11, 1930 2,113,913 Cragun Apr. 12, 1938 FOREIGN PATENTS 179,636 Great Britain May 8, 1922 

1. A HELIX WIRE ANODE FOR UDE IN A SYSTEM FOR ELECTROWINNING OF COPPER, OR THE LIKE, WHICH COMPRISES A CONDUCTIVE SUSPENSION BAR, A FRAME HAVING TOP, BOTTOM AND END RAILS, SAID FRAME BEING SECURED TO SAID SUSPENSION BAR AND HAVING A PERIPHERAL SHAPE SUITABLE FOR SUSPENSION IN AN ELECTROLYTIC TANK CONTAINING LIQUID ELECTROLYTE, AND A PLURALITY OF HELIXES OF WIRE WHICH IS NOT CORRODED BY THE ELECTROLYTE, EACH OF SAID HELIXES COMPRISING COILS OF UNIFORM DIAMETER AND HAVING ITS OPPOSITE ENDS CONNECTED TO OPPOSED RAILS OF SAID FRAME WITH THE LONG AXES OF SAID HELIXES LYING PARALLEL TO EACH OTHER A DISTANCE APART WHICH IS SUBSTANTIALLY LESS THAN THE OUTSIDE DIAMETER OF SAID COILS AND EACH OF SAID HELIXES HAVING ITS COILS TURNED IN THE OPPOSITE ANGULAR DIRECTION FROM THE ANGULAR DIRECTION OF THE TURNS OF THE COILS OF THE NEXT ADJACENT HELIX, THE COILS OF EACH HELIX BEING SPACED APART A DISTANCE SUFFICIENT TO CAUSE OVERLAPPING AND CONTACTING OF EACH COIL WITH THE ADJACENT COILS OF THE NEXT ADJACENT HELIX AND SAID HELIXES OCCUPYING SUBSTANTIALLY ALL OF THE AREA BOUNDED BY SAID FRAME, SO THAT THE EFFECTIVE WETTED SURFACE OF A UNIT AREA OF SAID ANODE WHEN IT IS PLACED IN OPERATIVE POSITION IN THE ELECTROLYTE IN THE ELECTROLYTIC TANK IS MATERIALLY GREATER THAN THE EFFECTIVE WETTED SURFACE OF A LIKE UNIT AREA OF A PLANAR ANODE, SAID CONTACTING COILS OF WIRE PROVIDING CONDUCTIVE PATHS FOR THE DISTRIBUTION OF ELECTRICAL CURRENT OVER THE ENTIRE AREA OF THE HELIXES WITHIN SAID FRAME WITH A MINIMUM OF OHMIC RESISTANCE. 